Insulator



A. O. AUSTIN Jan. 15, 1935.

INSULATOR Filed Sept. 30, 1931 INVENTOR Patented Jan. 15, 1935 UNITED STA-TE S PATENT OFFICE INSULATOB;

of New Jersey Application September so, 1931, Serial Nemesis. serum. (or. 173-318) Thisinvention relates to insulators: rigidlyconnected together in series to form posts or stacks, and-has for oneof its-objects the provision ofconnecting means for such insulators which ill will be economical to manufacture, easy to install,- and efficient in operation; I

A further object is-to provide connectingmeans forinsulators which will permit easy removal F lis avertical sectional view of an insulator havingoneembodimentj of the present invention 20, applied'thereto.

Eig. 2is.a.sec,tioni taken at right angles to Fig. 1'.

Eig.,3.- is,.a view similar to Fig. 2 showing a modification.

Fig. 4 isanendlview. andEig. 5 isa plan view Zlt of a key for holding the two parts-ofthe, insulator together.

In rigidly connected insulators more particularly those used for disconnecting switches or supporting bushings, it is desirable to make the insulators up in sections so that they may be readily assembled or disassembled and so that the loss of a part will not necessitate the loss of the other members. While it is comparatively easy to bolt the metal parts attached to the insulators together, considerable difliculty is encountered in providing a strong mechanical connection at low cost and one which does not materially impair the electrical properties of the insulator by reducing the fiashover voltage due to the projection of corners or parts.

In my improved connection, means are provided for forming an efflcient joint or connection both electrically and mechanically. Fig. 1 shows an insulator having dielectric members and 11 to which a cap 12 and a pin 13 are attached by cement or other suitable means. The pin is pref erably provided with a base flange or an enlargement 14, arranged for connection with the cap of an adjacent insulator in a stack, as shown at the top of the figure. Where several insulators are mounted together, it is necessary to provide a strong mechanical joint between the flange 14 and the top of the cap 12.

In the form shown in Figs. 1 and 2, this is accomplished by using a key 15 fitting in dovetail slots 16 and 17.1'in the=capz12"and.base' 14' respectively. The key-:15 locks thetwopartstogether. This key: is preferably constructedlto permit; of sometolerance or. irregularity in the connected parts and, at the same time, developthe necessary pressure between the base l4 andtop of the cap 12 to insure rigidity. In general, the keycanbe used to hold the parts together both forbend ing. and torsional moments. lf desired, addition-- a1 keys-or pins 18'may be usedzforinsuring tightness. The main key 15 may'be shoved into position and if the keys 18' arev slightly larger than the vertical space provided for them, they may be forced into-position, tendingto-increase the locking effect of the key 15. The keys l8 preferably have a slighttaper'whenused for thispurpose or have a chamfered end so that they may be forced intoposition. The key'member 15 may be made in a number-of different forms. One method of construction is to=make this member out of sheet metalstrips having slits inthe edges forming tongues, alternate ones of which are bent upward and downward respectively so that onepair will come into-contactwith theslot in the cap, and the adjacent paircome'in contact with the'slot in theconnected'base. Thismethod makes itpossible toprovide sufllcientresiliency to overcome irregularities and, at the same time, insures adequate pressure between the parts.

In order to assemble two parts together, the key is forced through the slots by any convenient means such as a small hydraulic press or a screw member similar to a seat clamp. It is evident that if it is desired to disassemble the insulators at any time, this may be readily carried out by forcing the key member out of the slot, thus making it possible to assemble the desired number of units. Very careful alinement may be provided either by the key member or by additional pins 18 or dowels 20, as shown in Fig. 3.

Where a single key only is used, the base and cap are not necessarily located definitely relative to each other in a direction in line with the slot. This location is determined by the keys or pins 18 or dowels 20.

Where slight clearance is provided as shown in Fig. 3, the keys may be given a waving form, as shown somewhat exaggerated in Figs. 4 and 5. Where a. waved type of key is used, it preferably does not bear on the cap and pin base at points which are directly opposite but rather at points which are displaced relatively of each other longitudinally of the key. By limiting the stifiness of the key, it is possible to provide for considerable latitude in fabrication as the key will simply bend to accommodate any difference in depth of the key way. This may be accomplished by a waved type of key in which there is a certain amount of resiliency or the result may be accom- 5 plished in a key which simply accommodates it- 0 them in .positiony.

self by exceeding the elastic limit distorting to accommodate any differences where necessary.

I claim: 7

1. An insulator comprising dielectric members having fittings secured thereto for connecting said dielectric members together in a stack, adjacent fittings in a stack having contacting faces and registering dovetail grooves in said faces, and a key having resilient diverging portions adapted to fit the registeringfdovetail grooves to hold said fittings together.

2. An insulator comprising dielectric members having fittings secured thereto, and means for locking the fittings of different dielectric members together to hold said dielectric members in stack formation,.said. means comprising a key having oppositely extended. resilient tongues adapted to engagedovetail slots in adjacent fittings to draw said fittings. together-rand hold 3. An insulator, stack comprising a plurality of dielectric" units each provided with a base and a cap,,the cap andbase of-;adjacent units being in engagement; and means for locking an engaging cap and base together. comprising registering slots in said capand base, a key for entering said slots to lock saidwcapv and base together, and means forexerting a separating force on a connected cap and base to tighten said key in said slots. I i

4. An insulator, .comprising a pair of dielectric members having fittings secured thereto, said fittings having contacting faces and registering grooves in said faces, saidv grooves having enlarged innerportions, and a keyhavingenlarged heads for. entering enlarged portions of said grooves,said heads havingbearing points spaced.

metal having" the edges thereof slit to form tongues, alternate tongues being bent in opposite directions transverse to the plane of the strip and adapted to engage inclined faces of registering grooves in adjacent elements to hold said elements together.

6. The combination with contacting. elements having registering dovetail grooves, of a key comprising a strip of sheet metal having diverging tongues extending from opposite edges thereof and inclined in opposite directions from the plane of said strip and disposed in said grooves ed units with fittings having engaging faces and registering grooves in said faces, said grooves being undercut to provide holding faces and a key disposed in said grooves and having yielding projections bearing upon the holding faces of said grooves at spaced points only, the bearing pointson the face of one fitting being offset rela tive to the bearing points on the face ofthe 8. An insulator comprising a plurality of units 25 connected fitting.

said units having openings forminga key-way with complementary bearingv faces onsaid re spective units, a key in said key-way and ene.

gaging ,said bearing faces at spaced intervals thereon for resiliently holding said units together, the points of engagement-of saidkey with the bearing face of one of said units being staggered relative to the points of engagementi with thebearing face of .the' other" of said units, and additional means for preventing relative movement of said units in the direction of the axis of said key.

9. The combination with pair of 1 elements having abutting faces and r'egistering dovetail grooves in said faces, of akey having resilient tongues disposed at opposite sides thereof'and engaging the faces of said grooves for holding said fittings together, and wedging means acting to separate said fittings to place said tongues under resilient stress.

, ARTHUR, o. A STTN. 

